Field of the Invention
Embodiments of the present invention relate generally to computer animation and, more specifically, to techniques for generating dynamic illustrations using principles of animation.
Description of the Related Art
An animator may create traditional cartoon-style animation by sketching a sequence of still images. Each image in the sequence may include the same or similar objects as previous images, with the shapes and/or positions of those objects adjusted incrementally to represent motion. When the images in the sequence are viewed in rapid succession, those objects may appear to change shape and/or move.
Animators typically employ a variety of techniques to increase the realism of animations. For example, an animator may draw a cartoon face with eyes having an exaggerated size to convey a “surprised” facial expression. Or an animator may draw a running cartoon character with overly stretched-out legs, suggesting that the character is taking very large leaps. Generally, animators exaggerate certain elements within animations to emphasize those elements to the viewer. Such emphasis may help the animations appear more lifelike and convincing to viewers.
The process of creating traditional cartoon-style animations can be very tedious for several reasons. First, the number of images required to create an animation can be exceedingly large. For example, a conventional animation is displayed at 24 frames per second (FPS), meaning that in order to create a 5-minute animation, an animator needs to manually draw 7200 relatively similar images. Second, the objects within each successive image must be drawn with precision in order to create the appearance of smooth, lifelike motion. Meeting this particular requirement becomes especially difficult when several thousand images must be created. Finally, sketching the dynamics of exaggerated actions, as discussed above, further complicates the process of creating the overall sequence of images because extra care is required to convey those particular effects.
In view of these difficulties, computer-based tools have been created to automate certain aspects of the animation process. However, these conventional tools suffer from a number of drawbacks. First, conventional tools typically rely on underlying physical models of the objects being animated. Not only are physical models difficult to generate, these models usually must follow the laws of physics. As almost all viewers understand, though, cartoon-style animations do not necessarily obey the laws of physics. Consequently, tools that rely on physical models are oftentimes not very useful for creating cartoon-style animations.
Second, animators generally use a specific terminology that has evolved alongside animation. This animation-oriented terminology may refer to high-level animation effects such as squash-and-stretch, follow-through, and so forth. By contrast, conventional computer-based tools generally rely on low-level terminology and syntax that is associated more with physics and/or graphics processing than animation. For example, a graphics processing-oriented animation tool may refer to skeletons, influences, skins, voxels, and so forth. Because animators do not use the terminology associated with conventional physics and/or graphics processing-oriented tools, animators oftentimes find such tools difficult or impossible to use.
As the foregoing illustrates, what is needed in the art is a more effective approach to creating cartoon-style animation.